Jotto's helicopter winter flying guide

Are you addicted to RC helicopters? If you are like me, you turn into a monster if you're
unable to fly for a couple of weeks. So what do you do during a long winter? Dig yourself
into a cave and
hibernate until spring? Nah. You go flying, of course. There is no such thing as a
"helicopter flying season" -- you can fly the whole year round!

Ready for flight!

About me

I'm a helicopter addict (who turn into a monster if I can't fly for a couple of weeks). Cold
weather doesn't prevent me from flying, so I have gained some experience about
flying during winter time. Of course, the fact that I grew up in
Northern Norway and my
Sami heritage does help on my winter
survival skills!

You get kinda used to winter when you grow up here

About winter flying

Winter flying is as fun as summer flying. It may not be as comfortable, but at least you're
not pestered by insects. You need proper clothing, and there are certain things that you need
to be aware of. Oh, don't forget your thermos with hot coffee. If you don't have one, buy one!

All you need for a perfect day in the snow: helicopter, transmitter, lipos and some coffee!

The lowest temperature I've been flying in was -20°C (-4°F). Was it nice and warm?
Errr... no. Was it fun? Hell yeah!!

Disclaimer

First of all, a little disclaimer: this page is meant to share my experiences with winter
flying. Follow this guide at your own risk. Temperatures during winter will often be lower than
the specified temperature range for your gear (not that care much about THAT).

How cold weather affects the helicopter

Low temperature affects your helicopter in several ways:

Everything, especially plastic, becomes more brittle. If you crash, there is a higher
chance that your parts will be shattered. On the other hand, crashing into deep snow is
better than crashing into gravel!

Aluminum tail booms shrink. If you have a belt-driven tail, your belt will get slack.
As the tail boom adapts to the ambient temperature, you may need to tighten your
belt to prevent the belt from slipping during flight. A perhaps better solution is to
switch to a carbon fiber tail boom or switch to torque tube.

Ball links become more tight. Some people use a tool to expand the ball links and keep
a separate set of winter ball links. I don't do that, but I keep an eye on them.

Gyros may get confused, especially if you fly a warm helicopter that gets colder during
the flight. This may cause the tail to drift. Let the helicopter acclimatize outdoors
before flying it. Different gyros cope differently with low temperatures.

Clothing and gear

Clothing is very important. If you are freezing, your fingers won't react as precisely and as
quickly as usual. Moreover, how fun is it to fly if you're shivering? Buy a good snow
suit (like the one I have on the picture). Believe me, that is much warmer than having separate
winter jacket and trousers!

Wear a warm wool cap, even if it doesn't feel like your head is cold. Your body will
prioritize heat flow to your head. When it's starting to get cold, the blood flow to your limbs
will be reduced in order to keep your head and viscera warm. If you don't use warm headwear, you
will loose a lot of heat through your head.

Hand warmers

There are several types of hand warmers out there. Each have their advantages and disadvantages.
They can be used for more than warming your hands, so they are worth having a closer look at:

Disposable air activated hand warmers: These are cheap, last for 6-8 hours, but they
don't produce much heat. Little
Hotties warmers are fine.

Crystallisation hand warmers: These produce heat through an exothermic crystallisation.
They produce more heat than the disposable ones, but they only last for 20-30 minutes. They are
re-activated by cooking them. Personally, I find these to be the least useful type.

Charcoal hand warmers: Those burn a charcoal stick inside a little box. I have used them
previously, but they don't produce much heat. You can get them on
Ebay.

Catalytic lighter fuel hand warmers: These are my favorite! There is no flame in it --
it has a burner element that releases heat from a chemical reaction with air and lighter fuel.
They produce quite a bit of heat if they are not contained in their protective bag. You'll see some example
applications further down. Nice models are the
Zippo hand warmer and the
bigger Giant Peacock
hand warmer.

Keeping hands warm

Keeping your hands warm is perhaps the most tricky part. I'm using a
Raydiowarm. Some people
just can't get used to it, but I find it invaluable.

The Raydiowarm may get quite moist after a few flights. Open it and ventilate it quickly
after each
flight. The air has low heat capacity compared to the transmitter, so you wont' loose much
heat. You will however get rid of the moist air.

Throw in a couple of silica gel bags. That will absorb some of the moisture.

If the window keeps collapsing down onto the sticks (I hate that), put a 600-size blade holder onto the
transmitter's antenna. That will make the entire Raydiowarm more rigid. If this is not enough,
you can mod the Raydiowarm with a stiffer frame. See the description below.

When you're not flying (e.g. when you're drinking coffee), tuck small disposable hand
warmers around the sticks so that they don't get cold.

Use a catalytic hand warmer inside it on the coldest days. Just make sure that it doesn't
get underneath your transmitter and activates the bind button!

The sticks are made of metal on most transmitters. Metal conducts heat very efficiently.
In this context, it means that cold sticks steal a lot of heat from your
fingers! The solution is simple: use shrink wrap (the thick type used when soldering) on your
sticks. This will insulate the sticks, as rubber conducts less heat than metal. As a bonus,
your sticks become grippier. If you sand the shrink wrap, the sticks become even grippier.

If you want a "pro" solution that will keep your hands warm on even the coldest days, use a
HobbyKing tyre warmer. This produces a lot of heat, driven by a 2S or 3S lipo. It's easier
to use this than the catalytic warmer. See the description below.

Transmitter in Raydiowarm, with the Blade Holder TrickTM
and the Hand Warmer TrickTM

I added a strap for a Zippo hand warmer to the Raydiowarm. Now I get warm on one hand and cold
on the other. Perhaps I should add one on the other side as well!

Sticks with sanded shrink wrap. I was out of the black ones -- it had to be blue or pink!

The ultimate Raydiowarm solution

If you are serious about winter flying, you might consider doing some modifications to your
Raydiowarm.

The Ultimate Raydiowarm SolutionTM

I have used HobbyKing tire warmers inside the pockets where the stiff pads are. The tire warmers produce
enough heat to make it comfortable, even when they are inside the pockets. I have also used a thread
bar to shape a stiff frame that prevents the window from collapsing onto the hands. The frame is bent
into a wedge shape and fixed to the top with zip ties. The lipo fits nicely underneath the
transmitter.

There is also a sheet of plexi glass in the front. This is attached with double-sided tape and further helps
preventing the Raydiowarm from collapsing. The lower part of the frame also helps fixing the sheet
onto the front wall.

The heater temperature controller and a lipo alarm on the outside.

I never really liked the arrangement of the straps on the Raydiowarm. I removed the strap that is
supposed to go around the waist, fixed the other straps to the edge and sacrificed a transmitter strap
to make everything more ergonomically correct for myself. The exact arrangement of the straps depend
on how you prefer to hold the transmitter.

The outside. Note the thread bar which acts as a frame and prevents the window from touching the hands.

Lipos in the cold

Cold lipo batteries have lower voltage under load than warm batteries. You will notice that
your helicopter has less "pop" than during the summer. On the other hand, the air will be
denser when it's really cold, yielding better lift.

The main battery on helicopters will get warm when it's discharged. That helps on
performance.

Try to keep your lipos warm until you use them. I have a cheap camping heater box with
a catalytic pocket warmer inside it. After a few hours at the field in -5°C (23°F), I
measured +21°C (70°F) inside the box! That should be warm enough for the most delicate
lipo! Just make sure that you keep the lipo separate from the warmer.

Heater box with lipos and and Zippo hand warmer

Field charging

As a rule of thumb, lipos shouldn't be charged fully in less than 10°C (50°F), as
that will reduce battery life. I put the charger, PSU and lipos inside the heater box. When
I charge at 1000W, the charger and PSU produce enough heat in the box to maintain room
temperature, even if it's below 0°C outside!

Portable, self-heating charging station!

Nitro in the cold

I have limited experience with nitro engines. A few things worth mentioning are

In general, the air is denser when it's cold. That means you have to richen the engine

As long as you manage to start the engine, you will have plenty of power when the
engine gets warm. Try to start the engine while it's warm right after you take it outdoors, and
don't take too long (coffee) breaks.

Your receiver battery will not last as long as usual. Moreover, it will not get warmer during
flight like a main battery will. Purchase multiple rx packs, they are dirt cheap anyway!